Laser focusing aperture and method

Abstract

Light is focused in a system for electro-optically scanning and reading bar code symbols by an aperture stop having a first optical portion for optically modifying a first part of a light beam to have a beam cross-section of a known size within a depth of field in which a symbol to be read is scanned by the first beam part, and a second light-transmissive, optical portion bounding the first portion and operative for optically modifying and directing a second part of the light beam away from the first part.

We claim:  
     
       1. A light focusing arrangement in a system for electro-optically scanning and reading indicia, comprising: 
       a) a light emitter for emitting a light beam; and  
       b) an optical component impinged by the light beam and having a first optical portion for optically modifying a first part of the light beam to have a beam cross-section of a known size within a depth of field in which an indicium to be read is scanned by the first beam part, and a second light-transmissive, optical portion adjacent the first optical portion and operative for optically modifying and directing a second part of the light beam away from the first beam part.  
     
     
       2. The arrangement of  claim 1 , wherein the emitter includes a laser source for emitting the light beam as a laser beam. 
     
     
       3. The arrangement of  claim 2 , wherein the emitter includes a focusing lens for focusing the laser beam. 
     
     
       4. The arrangement of  claim 1 , wherein the light beam is visible, and wherein the second beam part is a visible aiming beam for illuminating an aiming region on the indicium. 
     
     
       5. The arrangement of  claim 1 , wherein the second optical portion bounds the first optical portion. 
     
     
       6. The arrangement of  claim 1 , wherein the first optical portion is a reflector for reflecting the first beam part to the indicium, and wherein the second optical portion is a light-transmissive substrate on which the reflector is mounted, the second beam part passing through and past the substrate. 
     
     
       7. The arrangement of  claim 6 , wherein the substrate is constituted of glass, and wherein the reflector is a coating deposited on an area of the glass. 
     
     
       8. The arrangement of  claim 1 , wherein the first optical portion is a light-transmissive element having a generally planar exit surface, the first beam part passing through and past the exit surface along a first direction; and wherein the second optical portion has generally planar reflecting surfaces that are inclined relative to the exit surface and are operative for reflecting the second beam part along a second direction. 
     
     
       9. The arrangement of  claim 8 , wherein the first and second directions are mutually orthogonal. 
     
     
       10. The arrangement of  claim 1 , wherein the optical component is constituted of transparent, synthetic plastic material. 
     
     
       11. The arrangement of  claim 1 , wherein the first optical portion is a focusing element having a curved exit surface, the first beam part passing through and past the exit surface along a first direction; and wherein the second optical portion has generally planar reflecting surfaces that are inclined relative to the first direction and are operative for reflecting the second beam part along a second direction different from the first direction. 
     
     
       12. The arrangement of  claim 1 , wherein the first optical portion includes a first focusing element having a first curved exit surface to focus a portion of the first beam part within a near depth of field, and a second focusing element having a second curved exit surface to focus another portion of the first beam part within a far depth of field which is farther away from the emitter than the near depth of field; and wherein the second optical portion has generally planar reflecting surfaces for reflecting the second beam part. 
     
     
       13. The arrangement of  claim 1 , wherein the first optical portion is an aperture, and wherein the second optical portion is a light-transmissive aperturing element for directing the second beam part away from the first beam part. 
     
     
       14. The arrangement of  claim 13 , wherein the emitter includes a focusing lens mounted within the aperture. 
     
     
       15. The arrangement of  claim 13 , wherein the aperturing element is an optical grating. 
     
     
       16. The arrangement of  claim 13 , wherein the aperturing element is a digital optical element. 
     
     
       17. The arrangement of  claim 13 , wherein the aperturing element is a hologram. 
     
     
       18. The arrangement of  claim 13 , wherein the aperturing element includes a plurality of light-transmissive segments objective for illuminating a plurality of aiming regions on the indicium. 
     
     
       19. An optical aperture, comprising: an optical component incident to light, the component having a first optical portion for directing a first part of the incident light along a first optical path, and a second light-transmissive optical portion bounding the first optical portion and operative for separating and directing a second part of the incident light along a second optical path different from the first optical path. 
     
     
       20. The optical aperture of  claim 19 , wherein at least one of the optical portions is a reflecting element. 
     
     
       21. The optical aperture of  claim 19 , wherein at least one of the optical portions is a transparent element. 
     
     
       22. The optical aperture of  claim 19 , wherein at least one of the optical portions is a focusing element. 
     
     
       23. An optical aperture of  claim 19 , wherein at least one of the optical portions is an aperture. 
     
     
       24. An arrangement in a system for electro-optically reading indicia, comprising: 
       a) a light emitter for emitting a light beam;  
       b) an optical component impinged by the light beam and having a first optical portion for optically modifying a first part of the light beam to have a beam cross-section of a known size within a depth of field, and for directing the first beam part to an indicium within the depth of field, the optical component having a second light-transmissive, optical portion for optically modifying and directing a second part of the light beam to the indicium to illuminate an aiming region on the indicium;  
       c) a detector having a field of view for detecting light from the first beam part that is reflected off the indicium; and  
       d) a scanner for scanning at least one of the first beam part and the field of view.  
     
     
       25. The arrangement of  claim 24 , wherein the first optical portion has a first focusing element to focus a portion of the first beam part at close-in distances relative to the emitter, and a second focusing element to focus another portion of the first beam part at far-out distances relative to the emitter. 
     
     
       26. The arrangement of  claim 24 , wherein the second optical portion has a plurality of light-transmissive segments for illuminating a plurality of aiming regions on the indicium. 
     
     
       27. A light focusing method during electro-optical scanning and reading of indicia, comprising the steps of: 
       a) separating a light beam into first and second parts;  
       b) optically modifying the first part of the light beam to have a beam cross-section of a known size within a depth of field in which an indicium to be read is scanned by the first beam part; and  
       c) optically modifying and directing the second part of the light beam away from the first beam part.  
     
     
       28. The method of  claim 27 , wherein step (c) is performed by directing the second beam part to the indicium for illuminating an aiming region on the indicium. 
     
     
       29. The method of  claim 27 , wherein the separating step is performed by an optical component having a first optical portion for performing step (b) and a second optical portion for performing step (c); and wherein the second optical portion is transmissive to the light beam. 
     
     
       30. The method of  claim 27 ; and further comprising the step of detecting light from the first beam part that is reflected off the indicium over a field of view; and the step of scanning at least one of the first beam part and the field of view.